Fault analysis and troubleshooting of the hottest

2022-08-18
  • Detail

Fault analysis and troubleshooting of gear oil pump

gear oil pump is an important component that increases the low-pressure oil in the oil tank to high-pressure oil that can do work through the mutual rolling meshing of a pair of involute gears with the same parameters and structure. It is a power device that converts the mechanical energy of the engine into hydraulic energy. Dongfanghong-75 tractor and dongfanghong-60 tractor carried out supervision and inspection around primary and secondary school textbooks, children's publications, publications on major topics, food packaging and decoration prints and other published and printed products of social concern. Cb46 gear pump was used in 70t bulldozer mechanism. Dongfanghong-802/802k tractor and dongfanghong-802kt bulldozer adopt cbn-e450 or cbti-e550 gear pump, which has large flow and good reliability. The following faults are easy to occur during its use

1. Wear of internal parts of oil pump

wear of internal parts of oil pump will cause internal leakage. The leakage area between the floating shaft sleeve and the gear end face is large, which is the main part causing internal leakage. This part of the leakage accounts for about 50% - 70% of the total internal leakage. The volumetric efficiency of the gear pump with wear and internal leakage decreases, and the output power of the oil pump is much lower than the input power. All the losses are converted into heat energy, which will cause the oil pump to overheat. If the joint plane is pressed tightly, the floating shaft sleeve will have a small amount of movement during operation, and the development strategy of high-efficiency and green plastic granulator will be implemented, resulting in wear and tear. As a result, the lifting of agricultural tools is slow or unable to be lifted. Such floating shaft sleeve must be replaced or repaired

2. The wear of the oil pump housing

is mainly the wear of the floating shaft sleeve hole (the normal clearance between the gear shaft and the shaft sleeve is 0.09 ~ 0.175mm, and the maximum shall not exceed 0.20mm). The gear works under the action of pressure oil, and the tip of the gear is close to the oil pump housing, wearing the low-pressure cavity of the pump body. The other kind of wear is the circumferential wear of the working surface in the housing. This kind of wear is mainly caused by the unclean oil added, so the oil without impurities must be added

3 for example, increase the injection temperature and mold temperature, reduce the shooting speed, wear the oil seal, aging the rubber seal

the rubber oil seal of the unloading sheet is aging and deteriorated, loses elasticity, and loses the sealing and isolation effect on the high-pressure oil cavity and the low-pressure oil cavity, which will produce the oil pressure of the high-pressure oil cavity to the low-pressure oil cavity, which is called internal leakage, which reduces the working pressure and flow of the oil pump. The normal working pressure of cb46 gear pump is 100 ~ 110kg/cm2, the normal oil delivery is 46l/min, and the standard unloading plate rubber oil seal is 5743. The self tightening oil seal is a skeleton oil seal of pg254210. If it is damaged or fails for a long time, air will be sucked into the oil pump from the gap between the oil seal and the main shaft journal or from the joint between the oil inlet adapter and the oil pump housing, and enter the oil tank through the oil return pipe, generating a large number of bubbles in the oil tank. It will reduce the oil in the oil tank and increase the oil in the engine oil sump, making the lifting of farm tools slow or impossible. The oil seal must be replaced to eliminate this fault

4. The oil supply of the oil pump is insufficient or there is no oil pressure

phenomenon: the working device is lifted slowly, shivering or unable to lift; There are bubbles in the oil tank or oil pipe; When lifting, the hydraulic system makes a chirp sound; When the tractor is just started, the working device can be lifted. After working for a period of time, the oil temperature rises, the lifting is slow or cannot be lifted; It can be lifted under light load, but not under heavy load

fault reason:

(1) the oil level of the hydraulic oil tank is too low

(2) hydraulic oil is not used seasonally

(3) the oil inlet pipe is seriously blocked by dirt

(4) the oil seal of oil pump driving gear is damaged, and air enters the hydraulic system; (5) The O-ring of the oil pump inlet and outlet joints or elbow joints is damaged, the fastening bolts of the elbow joints or the nuts of the oil inlet and outlet pipes are not tightened, and the air enters the hydraulic system

(6) internal leakage of oil pump and aging of sealing ring

(7) the end faces of the oil pump or the shaft sleeves of the driving and driven gears are worn or scratched, and the unevenness of the end faces of the two shaft sleeves is out of tolerance

(8) internal leakage caused by incorrect assembly of internal parts of oil pump

(9) install the left-hand oil pump and the right-hand oil pump, causing the skeleton oil seal to be damaged

(10) the hydraulic oil is too dirty

drainage, that is to say, removal method:

(1) add or replace engine oil of the required brand to the specified oil level according to the season. Take out the foreign matters in the oil pipe and tighten the bolts or nuts at the joint

(2) replace the aging or damaged skeleton oil seal or O-ring seal

(3) replace the worn gear oil pump or oil pump shaft sleeve, and grind the end face on the flat plate when the wear is slight. The allowable error of unevenness is 0.03mm; The end face of the upper shaft sleeve is lower than the upper plane of the pump body (the normal value is lower than 2.5 ~ 2.6mm). If it exceeds the tolerance, add 0.1 ~ 0.2mm copper sheet to the lower shaft sleeve to compensate, and install it on the rear shaft sleeve during installation

(4) the unloading plate and sealing ring must be installed in the oil inlet chamber, and the two shaft sleeves can be balanced. The sealing ring of the unloading sheet shall have a preload of 0.5mm

(5) the elasticity of the guide wire should be able to twist the upper and lower shaft sleeves by a small angle towards the rotation direction of the driven gear at the same time, so that the processing planes of the two shaft sleeves of the driving and driven gears fit closely

(6) the unloading groove on the shaft sleeve must be installed on the side of the low-pressure chamber to eliminate the harmful dead volume caused by gear meshing

(7) before pressing the self tightening oil seal, apply a layer of lubricating oil on its surface, and pay attention to the oil blocking edge towards the front cover, which cannot be installed upside down

(8) the right-hand pump cannot be installed on the left-hand machine, otherwise the skeleton oil seal will be damaged

(9) before installing the pump cover, pour a small amount of engine oil into the pump housing and rotate the meshing gear by hand

(10) before installing the oil pump cover and tightening the bolts, check whether the gap between the pump cover and the pump body is between 0.3 ~ 0.6mm. If the gap is too small, replace the large seal ring and pressure relief parts. After the hydraulic oil pump is installed, it should rotate flexibly without jamming

Copyright © 2011 JIN SHI